The ability for one person to monitor another person's extension is useful in a variety of situations. For example, a secretary can monitor a boss' extension, including whether the extension has a call offering or is in use. It is also useful if the monitoring party (e.g., the secretary) can perform call functions on a call destined for a monitored extension. These functions can include, for example, answering the call, transferring the call, placing the call on hold and sending the call to voicemail.
While extension monitoring exists in traditional, keyed telephone systems, existing systems are not capable of allowing a boss extension to share a portion of the boss' call stack with a secretary extension so that the secretary can perform call functions on calls in the boss' call stack. Also not present in existing systems is an ability of the secretary extension to reconfigure the device associated with the boss' extension.